It’s one thing to write a fantasy, but quite another to live one. For E L James, who wrote the best-selling “Fifty Shades” trilogy, her quiet West London existence has been transformed into the continent-hopping life of a famous and wealthy author.

“I never realized what this would be like,” James said in a phone interview last week from London. “My ambition for these books was just to see them in book stores. Everything over that has been fantastic. But it is overwhelming.”

The numbers back her up. The first in James’ erotic trilogy, “Fifty Shades of Grey,” reached the 1 million sales mark in the U.K. faster than any other adult paperback. It took only 11 weeks, compared with 36 for “The Da Vinci Code.” Her U.S. sales have now surpassed 16 million.

Currently, the trilogy holds the three top spots on The New York Times’ best-sellers list for combined print and e-book fiction. According to Entertainment Weekly, the royalties on her books would add up to a $1.3 million salary — per week.

This breakneck trajectory to success could be ego-inflating. But James, who is looking forward to her book-signing at Comic-Con this afternoon, exudes a down-to-earth and extraordinarily ordinary demeanor.

“I love the craziness of Comic-Con,” she said. “Last time I was there, I met a friend at a small plaza nearby. And she was in amongst lots of zombies. We felt like we were in zombie land. It was surreal and a lot of fun.”

Although James is shy, book-signings are not daunting at all for her.

“It’s so lovely to meet people who enjoy your story,” she said. “It’s a real joy.”

The “Shades” trilogy is the romantically racy tale of Ana Steele, a virginal college graduate, and Christian Grey, a ridiculously rich and handsome billionaire, who has a penchant for BDSM (Bondage, Discipline, Sado-Masochism). When told she may have single-handedly made BDSM a household acronym, James gives a hearty laugh.

“It’s very light BDSM, though,” she said. “I set out to write a passionate love story. I had read a little BDSM and I thought it was hot. So I started with the idea of (a newcomer) meeting someone involved in BDSM. Ana didn’t know anything about it. She didn’t know anything about sex, full stop. It’s her discovery that’s interesting. Christian has this fantasy lifestyle; he’s capable in the boardroom and bedroom, and yet he’s broken. He’s a fixer-upper and Ana is everywoman. Women want to unravel this mysterious man.”

Q&A with E L James

Q: The origins of your first book, “Fifty Shades of Grey,” are rooted in the "Twilight" series. Do you see any commonality between that series and your trilogy as a whole?

A: Yes, it started as fan fiction. I was completely inspired by the "Twilight" series to write. I am a fierce Twihard. I think of both ("Shades" and "Twilight") as "Beauty and the Beast" kind of stories. They stem from that side of fiction.

Q: Your descriptions of interior settings are quite detailed. Did you feel readers would be attracted to that or is that something that came to you naturally?

A: It comes naturally. In fact, I have to see it to write it. I need choreography and geography. How do we move from one place to another? I have to know or I can’t move the characters around the room. I would be writing and then pulling my husband around, figuring out how we’d do this or move that way. (laughs) We were fully clothed. It was just so I could get it in my head.

Q: Some people say the term “mommy porn” for your books is degrading. What’s your opinion of the term?

A: I like to think you can’t own anybody’s response to your book. Mummy porn is a nice, short, convenient – and, frankly, lazy – way for journalists to describe the book.

Q: Some readers have the theory that because women are more empowered in the workplace now, they like fantasies in which women are submissive to their lovers. What do you make of that theory?

A: There is plenty of room for play in all relationships. I think Christian is fantastic on paper but would be very difficult to live with in reality. But letting someone take control of things is a fantasy for women – and for men sometimes.

Q: Are you planning a new series from Christian’s point of view?

A: I never say "never." But I need a holiday before I think of writing anything.

Q: Can you share anything about the upcoming film based on "Shades?"

A: So far, it’s been good fun, and I hope to God it stays that way. I’m enjoying the process. If there was something to talk about, I would. But there’s no news.

Q: How are you staying sane during this crazy whirlwind?

A: I take one day at a time. That’s the only thing I can do. At the end of each day, I feel like a nice glass of Sauvignon Blanc.

Q: Just one?

A: (with a laugh): Well, maybe two.

Q: Is your visit here part of a bigger U.S. tour? What’s next on your agenda?

A: Actually, I’m going on holiday afterwards. My family will be joining me.

Q: Are you going in disguise?

A: I don’t think people really know who I am. I hope not. So I think I can vacation peacefully.